Thursday

November 26, 2015
Posted by **Michelle** on Wednesday, December 10, 2008 at 10:44pm.

A man pulls a 10-kg box across a smooth floor with a force of 71 newtons at an angle of 23 degrees and for a distance of 97 meters. How much work, to the nearest joule, does he do?

--------------------------------------------------------------------------------

2

If the floor in the previous question is angled upward at 11.7 degrees and the man pulls the box up the floor at constant speed, what is the work he does to the nearest joule?

--------------------------------------------------------------------------------

3

In Problem 2, to the nearest joule, what is the work done by gravity?

--------------------------------------------------------------------------------

4

In Problem 1, if the box starts from rest, what is its final kinetic energy (to the nearest joule)?

--------------------------------------------------------------------------------

5

If the mass of the box in the previous problem is 17 kilograms, what is its final speed to the nearest tenth of a meter/sec?

--------------------------------------------------------------------------------

6

You are traveling in your 1542-kg car at 6 m/s and wish to accelerate to 19.2 m/s in 4 seconds. How much work, to the nearest joule, is required?

--------------------------------------------------------------------------------

7

In the previous problem what is the average power to the nearest watt?

--------------------------------------------------------------------------------

8

What is the equivalent (nearest) horsepower in Problem 7?

--------------------------------------------------------------------------------

9

Assuming you have a bow that behaves like a spring with a spring constant of 70 N/m and you pull it to a draw of 59 cm, to the nearest joule how much work do you perform?

--------------------------------------------------------------------------------

10

In the previous problem, to the nearest tenth of a m/s, what is the speed of the 107-gram arrow when it is released

- Physics -
**drwls**, Thursday, December 11, 2008 at 10:45amAll of these problems involve using the law of conservation of energy. In the first five, you have to calculate how far the box rises to compute the change in potential energy. Use gelometry for that. In #6, compute the change in kinetic energy of the car of the car. #7 and #8 require dividing work done by the time it takes to do the work

If you are unable to do these, I am skeptical about whether you did 20 other problems correctly.

Show your work if you need further help

- Physics -
**Bob**, Tuesday, November 16, 2010 at 1:13pmwork=forcexdistancexsin(angle)